ξύμβλητο

From LSJ

νᾶφε καὶ μέμνασ' ἀπιστεῖν → keep a clear head and remember not to believe a thing (Epicharmus fr. 250)

Source

Russian (Dvoretsky)

ξύμβλητο: эп. 3 л. sing. aor. 2 med. к συμβάλλω.